I had the privilege of meeting Dr. Shlain in 2007. He told me he was planning a new book called Leonardo’s Brain which would focus on his growing understanding of human intelligence.

As a long time student of human intelligence, this was a topic that greatly interested me. …

Today, I was reminded of that three year old conversation, I thought I must have missed the publication date, so googled Leonard only to discover he had died, and that his book was still unpublished.

At first I thought perhaps the book had been lost, but fortunately, the book was finished before his death. Humanity is blessed to have Leonard’s final thoughts to help us understand the human condition.

Today, it is my privilege to share his son’s thoughts on his father passing, and on his father’s scientific work, this article was originally posted shortly after his father’s death in September 2009.

Left Brain, Right Brain, and Ironies of the Heart

Jordan Shlain, MD

I was rummaging through some old college files last month and stumbled across a paper I wrote for my Physiology 101 class on May 8, 1989, at U.C. Berkeley, titled “Learning and neural adaptation: Postsynaptic potentiation.” It was an analysis of neuronal plasticity. After reading it, I was reminded that the map that charts the path of understanding neuroscience is byzantine, sophisticated, and very exciting.

Neuroscience is one of the last great medical frontiers. Encompassing biochemical neurotransmitters, high-definition imaging, computer-aided modeling technology, and much more, this field assists us in deciphering the staggering complexity of the human mind. And there is the irony about the cognitive and intellectual horsepower of the mind invested in the study of itself.

I am acutely aware of one individual, my late father, who devoted the last twenty-five years of his life to demystifying the nuance of the parallel and distinct universes that are the right and left brain. His interest and scope transcend the focused study areas in neuroscience; he bridged the nano and macro and wove a tapestry as elegant in its simplicity as the human brain itself. He focused on the ultimate byproduct of neuroscience—behavior. As a genetic pupil, I will do my best here to illuminate some of the works of my father, including the as-yet-unpublished one he finished just before he died in May.

Leonard Shlain asked many questions in his life. The one that started him on his journey for understanding the right brain/left brain dichotomy took place at the Museum of Modern Art in New York. My sister, who was and still is a talented artist, asked him, “Dad, could you please describe that to me? I don’t understand it,” as she pointed to a piece of abstract modern art. He paused and realized that the zeitgeist of modern art was as inexplicable and inscrutable as was the world of quantum physics.

In his first book, Art and Physics: Parallel Visions in Space, Time and Light, he posited that the right brain describes the world through the medium of art while the left brain describes the same world using science as its medium. Furthermore, the right brain is evolving slightly ahead of the left brain, such that major shifts in artistic movements precede corresponding discoveries in physics. My father’s example of this was Picasso’s Cubism and Einstein’s subsequent Theory of Relativity. Cubism was an artistic movement that described on canvas the idea that you could look at one image from multiple perspectives from one vantage point. The theory of relativity says that space and time are one and the same, and what you see depends on where you are in space-time. Historically, artists and physicists have paid scant attention to one another’s work, but he develops the idea that the most innovative artists nonetheless prepare the public’s mind for expanded conceptions of reality.

Dad’s next exploration into the mystery of hemispheric lateralization began with the question: What happened five thousand years ago that changed the sex of god of Western religion? Why did Western civilization transform from an abundance of goddess-centric, matrilineal, and matriarchal societies into a singular, strict patriarchal one? The answer, upon close inspection, is the left brain: The “male” brain wrested control of the vox populi. The male brain was the hunter brain, the dispassionate and linear brain. The sequential property of the written word made acquisition and adoption by the left brain easy. The right brain, or “feminine” brain, was holistic, abstract, image based, and nurturing. The complete control of the written word did not allow the right brain to have a seat at the table of organized religion, especially given that the first known written words are the Ten Commandments—and that the third commandment says there shall be no art (Idols). The Alphabet Versus the Goddess: The Conflict Between Word and Image has the audacity to question myths, legends, history, and science all through The lens of neuroscience.

The third work, Sex, Time and Power: How Women’s Sexuality Shaped Human Evolution asked another question: Why did big-brained Homo sapiens suddenly emerge some 150,000 years ago? He argues that profound alterations in female sexuality hold the key to this mystery.

Long ago, due to the narrowness of her bipedal pelvis and the increasing size of her infants’ heads, the human female began to experience high childbirth death rates, precipitating a crisis for the species. Natural selection adapted her to this unique environmental stress by drastically reconfiguring her hormonal reproductive cycle. Her estrus disappeared and menses mysteriously entrained with the periodicity of the moon. Women formulated the concept of a month, which in turn allowed them to make the connection between sex and pregnancy. Upon learning the majestic secret of time, these ancestral females then gained the power to refuse sex when they were ovulating. Men were forced to confront women who possessed minds of their own.

Women taught men about time and the men used this knowledge to become the planet’s most fearsome predators. Unfortunately, they also discovered that they were mortal. Men then invented religions to soften the certainty of death. Subsequently, they belatedly grasped the function of sex. The possibility of achieving a kind of immortality through heirs drove men to construct patriarchal cultures whose purpose was to control women’s reproductive choices.

As you may sense by this point, the good Dr. Leonard Shlain was not afraid to ask tough questions, research voraciously, and beautifully synthesize disparate themes. His final question, which is the topic of his latest and still-unpublished book, does not ask a question—it makes a statement. Leonardo da Vinci is likely the only human being in recorded history who could have won a Nobel Prize in both art (right-brain dominant) and in science (left-brain dominant). This final masterpiece is the study and exploration of Leonardo da Vinci’s brain. Rather than paraphrase, I will allow you to peruse some of the book’s nuggets:

“ … How, then, are we to explain the fact that in all of history there has been only one person who combined a genius so spectacular that he incandescently illuminated both the fields of art and science? Why does Leonardo occupy his solitary niche in the history of humankind across thousands of cultures and generations? His uniqueness has continued to enthrall commentators throughout the nearly five centuries that have followed his death in 1519.”

“He gives precise instructions to painters how they should depict the penumbra of shadows and how to position objects relative to each other in a composition so that the laws of perspective are rigorously followed. The only contemporary artist he mentions by name, Sandro Botticelli, is taken to task for his lack of interest in faithfully adhering to the axioms of perspective. How then to explain the unsettling discovery, when carefully examining Leonardo’s paintings, that he cleverly violates the laws of perspective in all of them? These anomalies will be detailed in a later chapter. Leonardo is both an extraordinary left-brained academician obsessed with portraying perspective correctly, and a right-brained impish trickster who takes delight in fooling the viewer with perspectivist sleights of hand.”

“If creativity begins in the right brain, it must at some point make the journey across the great divide between the hemispheres. To translate an insight into words or action, the left hemisphere must be involved—but not always. In the kinesthetic arts, such as dance or basketball, the right brain may invent a creative maneuver never used by anyone before. In some cases there is no conscious input and the right hemisphere will simply put the innovation in place in the middle of a routine or game. In general, however, the left lobe must translate the insight into words, or verify the insight using paint or equations. This step requires that the insight be formally introduced to the left lobe.”

“After arising in isolation in the right hemisphere, the creative insight must climb aboard the corpus callosum express to be ferried across to the left side of the brain. This raises the question: Is the corpus callosum merely a conduit or does it serve a higher, more integrative function? The corpus callosum is the most poorly understood structure in the human brain, and it also happens to be the largest. Arching over the midline, the corpus callosum is an enormous band of neurons numbering well over 200 billion. Neuroscientists are of two minds as to what this broad band of connecting fibers function is. The first is a down-to-earth, no-nonsense approach that posits that the corpus callosum serves only as a conduit that allows the right hand to know what the left hand is doing and vice versa. The opposing theory proposes that the corpus callosum integrates information from each side and represents an über hemisphere in that it functions as a third brain producing something qualitatively different from what the right and left brain generate individually.”

I will leave you, teary eyed, with the last paragraph of the epilogue, written May 8, 2009—twenty years to the day after I finished my undergraduate paper.

“As I write this, I am grateful for the extended time. My MRI, which had revealed the doubling of the size of the tumor the last time, showed that with the treatment of Avastin, my determination to live, and the phenomenal outpourings of prayers and good wishes from people, some of whom I know and many others who have only read my books, the tumor has shrunk to over two-thirds the size. I am walkin’ and talkin’, two things that are the left brain’s province, an indication of the left’s control of body movements and speech which are currently not showing any disability. I hope to see you in the spring of 2010, when the book will be published.”

On May 11, four days after completing his book Leonardo’s Brain, my father, himself a modern-day Leonardo, succumbed to a brain tumor. Irony squared.

Jordan Shlain, MD, is Leonard Shlains’s only son and a practicing Internist in the San Francisco area. I emailed him today. He wrote, “My father’s yet unpublished work is still mired in the gears of the publishing world. My elder sister, Kimberly is working on getting it published. If it is not published, we will likely make it an ebook.”

Kimberly Brooks is Leonard Shlain’s oldest daughter. She writes about her father here and here-2.

Tiffany Shlain is Leonard Shlain’s youngest daughter. She talks about her father here.